Walking down a street in Stockholm in August, I noticed an old-looking small car that I did not recognize parked at a curb. The badge on the grill said DAF, which I recognized as a Dutch manufacturer of trucks. An unremarkable European small car from a company that abandoned the car business years ago, although perhaps interesting as a survivor, I thought.
A look at the badges on the rear of this DAF told me that it was actually quite remarkable. It was a DAF 66, produced from 1972 to 1975, continuing until 1980 as the Volvo 66 after Volvo acquired DAF’s passenger car business in 1975. The badge on the bumper announced the car’s claim to fame: the Variomatic transmission, a pioneering continuously variable transmission (CVT) first sold to the public in 1958. It was the first commercially successful CVT, preceding any other use of a CVT in a car by a quarter century. (Some tractors and ATVs used CVTs as early as the 1960s.) The CVT is currently far more popular than when the Variomatic was the only one in cars, with Nissan, Honda, Subaru, Toyota, Mitsubishi, Audi, BMW (Mini), and Chrysler (Dodge and Jeep SUVs) all offering CVTs.
The basic principle behind the Variomatic CVT was simple. It used two V-shaped pulleys connected by a drive belt, and it varied the gear ratio by moving the belt along the V’s of the pulleys. DAF used a rubber belt in the Variomatic, which limited the transmission’s strength but was adequate for the power output and weight of a 1960’s four cylinder economy car. More recent CVTs use steel belts for the greater strength needed for more powerful and heavier cars.
(Editor’s addition: Here’s a nice video of it in action, from underneath a 66.)
The Variomatic used a separate belt and pulley mechanism for each drive wheel. It served in effect as a CVT with a limited slip differential. This photo, of the transmission and rear axle assembly of a preceding DAF model, shows how DAF used swing axles with coil springs in its early Variomatic-equipped cars, giving them the unpredictable handling expected of swing axles.
DAF gave the 66 an entirely new rear suspension setup using a sophisticated De Dion axle with leaf springs. Usually found in expensive high performance cars such as Aston Martins, Lancias, and Maseratis, the De Dion axle avoided the camber changes of the swing axles and dramatically improved the handling of the 66 compared to its predecessors.
A significant disadvantage of the Variomatic in a compact car application is evident in this photo of a complete drivetrain. Observant viewers of the earlier color photo of the Variomatic may have noticed that the driveshaft connection is set up for a front engine/rear drive arrangement. This photo shows how much space the drivetrain occupied in a Variomatic-equipped DAF. The north-south engine, driveshaft, and Variomatic in the rear occupied a significant amount of volume, not a good feature in a family car with small dimensions. The rear wheel drive Variomatic would be an evolutionary dead end, phased out when the Volvo 66 ended production in 1980. The successor to the DAF/Volvo 66, the DAF-designed Volvo 343, dropped the Variomatic in favor of a rear-mounted conventional gearbox. Volvo went with front wheel drive in the next generation, the 440 of 1987, following the industry trend toward front wheel drive and its space efficiency in the compact car segment
Ironically, this DAF 66 had its interior crammed full of household items, making it one of the world’s least capacious automotive shipping containers. Still used like a pack mule after four decades, this car is remarkable for surviving since the early 1970’s apparently free of rust or major damage, and moreover for the unique drivetrain used by its manufacturer from 1958 to 1980. It is a survivor of an era when the international automobile market had a diverse variety of independent manufacturers, which produced many unusual designs before the automobile industry developed the basic formulas used in today’s cars.